Press Releases

July 13, 2006

Gilead Sciences and the Institute of Organic Chemistry and Biochemistry (IOCB) Establish New Academic Research Centre in Prague; Donation by Gilead Honors Leadership of Dr. Antonin Holy in Antiviral Drug Discovery and Development

FOSTER CITY, Calif. & PRAGUE, Czech Republic--(BUSINESS WIRE)--July 13, 2006--Gilead Sciences, Inc. (Nasdaq:GILD) today announced a donation to The Institute of Organic Chemistry and Biochemistry at the Academy of Sciences of the Czech Republic (IOCB) for the establishment of a Gilead Sciences Research Centre. Gilead will provide a $1.1 million annual donation to IOCB for an initial five-year term to fund the Centre's operations and ongoing research activities.

IOCB will use the donations to establish and support the Gilead Sciences Research Centre, which will consist of selected research groups led by the scientists at IOCB. In addition, Gilead and IOCB will establish the Gilead Distinguished Chair in Medicinal Chemistry. Dr. Antonin Holy, IOCB, will be the first to hold the position of Distinguished Chair and will continue to lead research efforts in nucleoside and nucleotide drug discovery. The operation of the Research Centre will be governed by a Steering Committee and monitored by an Advisory Board.

In 1991 and 1992, Gilead entered into license agreements with IOCB and the Rega Institute for Medical Research, Katholic University in Leuven, Belgium that cover a large number of nucleotide analogue compounds and structures. Several of these nucleotide compounds (specifically HPMPC, PMPA and PMEA) discovered through a collaborative research effort between Dr. Antonin Holy and Dr. Erik DeClercq, Rega Institute, were developed by Gilead, resulting in Vistide(R) (cidofovir injection) for the treatment of CMV retinitis in AIDS patients, Viread(R) (tenofovir disoproxil fumarate) for the treatment of HIV infection and Hepsera(R) (adefovir dipivoxil) for the treatment of chronic hepatitis B.

"The compounds that Gilead licensed from IOCB represent an important component of our product portfolio and, most importantly, have helped deliver new treatment options to hundreds of thousands of patients suffering from HIV and chronic hepatitis B," said John C. Martin, President and CEO, Gilead Sciences. "We are pleased to be able to honor the contribution of Dr. Holy and the productive collaboration between Gilead and IOCB over the years through this donation, which will fuel IOCB's leading role in scientific research and drug discovery."

"The scientific pursuit of new targets, new compounds and novel mechanisms for identifying or treating diseases is our most important priority," said Dr. Antonin Holy. "We have a long-standing and productive relationship with Gilead, and we are deeply appreciative of the company's support for this new Research Centre."

Today, Gilead and IOCB have also entered into a separate arrangement under which Gilead will provide patent services to the IOCB, and as part of this arrangement Gilead will have the first right of refusal to license technologies in certain therapeutic areas from IOCB.

About Gilead Sciences

Gilead Sciences is a biopharmaceutical company that discovers, develops and commercializes innovative therapeutics in areas of unmet medical need. The company's mission is to advance the care of patients suffering from life-threatening diseases worldwide. Headquartered in Foster City, California, Gilead has operations in North America, Europe and Australia. For more information, please visit www.gilead.com.

About IOCB

The Institute performs fundamental research in organic chemistry, biochemistry and related disciplines oriented mostly to medicinal and environmental applications. The Institute is involved in university level of education and supervises diploma and PhD studies.

Forward-Looking Statement

This press release includes forward-looking statements, within the meaning of the Private Securities Litigation Reform Act of 1995, that are subject to risks, uncertainties and other factors. These risks, uncertainties and other factors could cause actual results to differ materially from those referred to in the forward-looking statements. The reader is cautioned not to rely on these forward-looking statements. For these and other risks Gilead directs its readers to its Annual Report on Form 10-K for the year ended December 31, 2005 and the report on Form 10Q for the first quarter 2006 as filed with the U.S. Securities and Exchange Commission. All forward-looking statements are based on information currently available to Gilead and Gilead assumes no obligation to update any such forward-looking statements.

CONTACT: Gilead Sciences, Inc.
Susan Hubbard, 650-522-5715 (Investors)
Erin Edgley, 650-522-5635 (Media)
SOURCE: Gilead Sciences, Inc.